1. Field of the Invention
The present invention relates to access control, and, more particularly, to manually operated, electronically keyed locks and locking processes suitable for retrofitting existing appliances.
2. Description of the Related Art
Current designs for maintaining security of containers such as bank safe deposit boxes require attended access and, all too frequently, dual keys, to allow access to the various containers maintained. We have found that the use of dual keys has become increasingly expensive in terms of man hours consumed by the employees of the bank providing attendance to the customers of the bank. Historically, safe deposit locks as well as other locks, have used a keyed cylinder that is offset from the centerline of the casing for the lock, within the body immediately behind the front plate of the safe deposit door. It was the object of this design to accommodate a full sized set of mechanical tumblers within the casing immediately behind the front plate of the door. The economics of safe deposit box rental require that the casing of the lock be made narrow in order to provide a high degree of security for the door while minimizing the loss of volume of the door due to the presence of the casing for the lock. The offsetting of the centerline of the keyway in turn allows the use of a more conventional and secure design within the very narrow compartment doors, as well as within taller doors. By the expedient of placing the cylinder of the lock in the lower portion of the casing, below the centerline of the casing and vault, the key could lift a set of larger tumblers without requiring an undesirably larger lock casing. The economy of providing uniform lock design, over the years, for differing applications has resulted in an existing installed base of millions of these locks. While not all of these locks rely upon offset keyed cylinders (referred to as xe2x80x9cnosesxe2x80x9d in the trade), many do.
Four major lock manufacturers currently continue to produce locks with offset keyed cylinders, while at least two other manufacturer that have discontinued production, continue to have a large installed base. One of the most popular offset locks in the current market is the 4440 series left hand and right hand model manufactured by Sargent and Greenleaf. We have noticed a need to retrofit existing offset keyed cylinder locks with electro-mechanical locks, without expensive and inconvenient replacement of the doors, in order to minimize the man hours consumed by employees of banks that provide attendance to the customers, while the customers open their safe deposit doors, with a mechanical enhancement of blocking strength as well as an improvement of security over other processes, without a complex electrical contact system.
We have also noticed that authorized service mechanics often open locked mechanical safe deposit locks by first drilling a hole through the face of the cylinder plug, threading a sheet metal or self tapping screw into the hole and pulling the inserted screw with either a nose puller or claw hammer until the face of the cylinder breaks away to allow removal of the cylinder plug. The removal of the cylinder plug allows direct and immediate frontal manipulation of the tumblers until the lock is unlocked. Consequently, even though the faceplate of the safe deposit door may itself be strong enough to resist casual tampering, the susceptibility of the cylinder plug to quick removal by a single application of brute force deleteriously reduces the security of the entire drawer.
The Electronic Security System of U.S. Pat. No. 5,745,044 and U.S. Pat. No. 5,140,317 issued to Hyatt et al., is currently used to lock pay telephones. This design blocks a locking bolt, but does so from what we believe is a geometrically disadvantageous point. By virtue of the separate direct blocking of a bolt by a solenoid, the bolt is blocked off center from the centerline of the bolt. Moreover, the physically large lock cylinder and the inter-device discrete wiring between the solenoid and the other components inside the casing, as well as the electrical contact system for the lock cylinder, create several problems in our opinion. Furthermore, the difficulty of manufacture and installation of wiring, and the absence of both miniaturization and offsetting of the bolt blocking, suggest that there is little practical prospect of retrofitting the many existing offset nose locks. In addition, the routing and use of discrete wires causes problems of reliability and quality during manufacture and usage, absent tedious careful and consistent monitoring.
The rotatable keypad operated solenoid lock of Butterweck, et al, U.S. Pat. No. 5,845,523 for an Electronic Input And Dial Entry Lock, and the other various locks mentioned in that patent such as U.S. Pat. No. 4,831,851 for a Combination/electronic Lock System by Larson, U.S. Pat. No. 4,967,577 for an Electronic Lock With Manual Override by Gartner, et al, U.S. Pat. No. 4,899,562 for an Electronic Door Lock by Gartner, and U.S. Pat. No. 4,904,984 for a Combination Lock With An Additional Security Lock by Gartner, are variations of a dial operated combination lock, and lack the security, reliability and economy traditionally demanded for safe deposit boxes and drawers, while the Lock For A Safe-Deposit Box of Chieh-Chen Yen, et al., U.S. Pat. No. 5,495,733 inconveniently relies upon different keys for the renter of the safe deposit box and for the clerk of the bank, as well as a manually operated keypad.
It is therefore, an object of the present invention to provide an improved lock and process for restricting access to containers.
It is another object to provide a lock and process suitable for retrofitting containers previously secured by bitted and unbitted locks.
It is yet another object to provide a lock and process able to enhance the security of containers against unauthorized entry.
It is still another object to provide a lock and process able to electronically control access to the interior of secured containers.
It is still yet another object to provide a lock and process for electronically monitoring access to secured containers.
It is a further object to provide an electronically key controlled process and a cam assembly that may be configured as a single integrated electromechanical unit operable with an electronically controlled key, mated with either the existing lock cylinders of containers or with new lock cylinders, and retroactively fitted to secure those containers.
It is a still further object to provide an electronically key controlled process and integrated electromechanical cam assembly that may either be installed as a retroactively fitted component part of an existing locking mechanism with a minimum of modifications of the locking mechanism, or alternatively, be incorporated into a complete locking mechanism.
It is still yet a further object to provide an electronically key controlled process and integrated electromechanical cam assembly that may be retroactively installed as a component part of locking mechanisms previously installed in lockable containers by using existing screw patterns and key holes of those containers.
It is an additional object to provide an electronically key controlled process and integrated electromechanical cam assembly able to be mated with either bitted lock cylinders or with unbitted cylinder plugs.
It is a still additional object to provide an electronic cam and cam locking process endowed with simplified interconnections between the components of the lock, and that is amenable to simplified manufacture.
It is a yet additional object to provide an electronic cam and cam locking process endowed with an enhanced mechanical strength.
It is still yet an additional object to provide an electronic cam and cam locking process that indirectly blocks the cam.
It is also an object to provide a locking cam and cam locking process that drives and locks the bolt from its relative center.
These and other objects may be achieved with a process requiring either electronic conformance of a key to an electronic circuit carried by a cam driving a bolt or both mechanical conformance and electronic conformance of the key to both a cylinder plug and to the electronic circuit in order to enable the cam to drive the bolt between a locked position and an unlocked position. One embodiment may be constructed with a housing bearing an optimally positioned hole centered upon first axis, a bolt supported by the housing an moving transversely relative to the first axis to protrude beyond the housing to an extended, and locked, position and to retract within the housing to a retracted, and unlocked, position, and the cylinder plug of the lock cylinder perforated by a centrally positioned keyway, having an exposed circumferential surface surrounding the keyway rotatably fitted within the optimally positioned hole, and rotating within the optimally positioned hole in response to rotational force applied by a key conformingly corresponding to the lock through an arc centered upon the first axis. A cam is positioned within the housing to rotate with the cylinder plug as the key conformingly corresponding to the lock manually applies a rotational force to the cylinder plug as the key is manually rotated through the arc. A member eccentrically positioned relative to the first axis, extends between the cam and the bolt to drive the bolt between the extended and the retracted positions as the cylinder plug is rotated through the arc. An electronic circuit containing a memory and a microprocessor, that is mounted upon and supported by the cam to rotate with the cam through the arc, determines electronic conformance of the key and operationally responds to digital data carried by the key to electronically activate a release mechanism that is spaced-apart from the cylinder and eccentrically positioned away from the first axis. The circuit is functionally activated by the electronic circuit in response to mechanical and electronic conformance between the key and both the cylinder plug and the electronic circuit, to move between a deployed position preventing rotation of the cam relative to the housing, and a released position accommodating the rotation of the cam relative to the housing. Optionally, the first axis may be positioned to locate the cylinder plug off-center and toward one side of the lock""s casing while the cam is positioned to rotate around a second and different axis in response to rotation of the cylinder plug and either electronic conformance to an electronic circuit carried by the cam, or both mechanical conformance to the cylinder plug and electronic conformance to the electronic circuit.